Direct determination of nitrogen functional groups in kerogen under kinetically well defined conditions
- Exxon Research and Engineering Co., Annandale, NJ (United States)
Recent developments in X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) spectroscopy methods have made it possible to directly quantify nitrogen functionalities in complex solid and nonvolatile carbonaceous systems such as coal and kerogen. The kinds of nitrogen forms present in different organic matter type kerogens and the influences of sample maturity have not yet been established via these new direct methods. It is generally recognized that much of the nitrogen in coal and kerogen originated from the remains of organisms rich in amino groups yet it is believed that heterocyclic nitrogen compounds are the dominate forms present in petroleum, kerogen and coal. For coal, XPS results show that pyrrolic nitrogen is the most abundant form, followed by pyridinic and quaternary types. The relative amount of different nitrogen decreases with increasing coal ranks XPS has been used in the present work to quantify the amounts of different nitrogen functionalities initially present in Green River kerogen (Type 1) and Bakken kerogen (Type II) and to follow the changes that happen as a result of low-temperature pyrolysis under kinetically well defined conditions. Small amounts of amine and quaternary type nitrogen species were found in fresh Green River kerogen samples in addition to the more abundant pyrrolic and pyridinic nitrogen forms. Following pyrolysis to simulate the early conversion chemistry kerogen to light gases, pyrrolic and pyridinic nitrogen are the dominant forms. These results are compared to the results for Bakken kerogen and coal.
- OSTI ID:
- 126541
- Report Number(s):
- CONF-950402--
- Country of Publication:
- United States
- Language:
- English
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